<?php

/**
 * @file
 * Install functions for PostgreSQL embedded database engine.
 */


// PostgreSQL specific install functions

class DatabaseTasks_pgsql extends DatabaseTasks {
	protected $pdoDriver = 'pgsql';

	public function __construct() {
		$this->tasks[] = array(
				'function' => 'checkEncoding',
				'arguments' => array(),
		);
		$this->tasks[] = array(
				'function' => 'checkPHPVersion',
				'arguments' => array(),
		);
		$this->tasks[] = array(
				'function' => 'checkBinaryOutput',
				'arguments' => array(),
		);
		$this->tasks[] = array(
				'function' => 'initializeDatabase',
				'arguments' => array(),
		);
	}

	public function name() {
		return st('PostgreSQL');
	}

	public function minimumVersion() {
		return '8.3';
	}

	/**
	 * Check encoding is UTF8.
	 */
	protected function checkEncoding() {
		try {
			if (db_query('SHOW server_encoding')->fetchField() == 'UTF8') {
				$this->pass(st('Database is encoded in UTF-8'));
			}
			else {
				$replacements = array(
						'%encoding' => 'UTF8',
						'%driver' => $this->name(),
						'!link' => '<a href="INSTALL.pgsql.txt">INSTALL.pgsql.txt</a>'
				);
				$text  = 'The %driver database must use %encoding encoding to work with Drupal.';
				$text .= 'Recreate the database with %encoding encoding. See !link for more details.';
				$this->fail(st($text, $replacements));
			}
		}
		catch (Exception $e) {
			$this->fail(st('Drupal could not determine the encoding of the database was set to UTF-8'));
		}
	}

	/**
	 * Check PHP version.
	 *
	 * There are two bugs in PDO_pgsql affecting Drupal:
	 *
	 * - in versions < 5.2.7, PDO_pgsql refuses to insert an empty string into
	 *   a NOT NULL BLOB column. See: http://bugs.php.net/bug.php?id=46249
	 * - in versions < 5.2.11 and < 5.3.1 that prevents inserting integer values
	 *   into numeric columns that exceed the PHP_INT_MAX value.
	 *   See: http://bugs.php.net/bug.php?id=48924
	 */
	function checkPHPVersion() {
		if (!version_compare(PHP_VERSION, '5.2.11', '>=') || (version_compare(PHP_VERSION, '5.3.0', '>=') && !version_compare(PHP_VERSION, '5.3.1', '>='))) {
			$this->fail(st('The version of PHP you are using has known issues with PostgreSQL. You need to upgrade PHP to 5.2.11, 5.3.1 or greater.'));
		};
	}

	/**
	 * Check Binary Output.
	 *
	 * Unserializing does not work on Postgresql 9 when bytea_output is 'hex'.
	 */
	function checkBinaryOutput() {
		// PostgreSQL < 9 doesn't support bytea_output, so verify we are running
		// at least PostgreSQL 9.
		$database_connection = Database::getConnection();
		if (version_compare($database_connection->version(), '9') >= 0) {
			if (!$this->checkBinaryOutputSuccess()) {
				// First try to alter the database. If it fails, raise an error telling
				// the user to do it themselves.
				$connection_options = $database_connection->getConnectionOptions();
				// It is safe to include the database name directly here, because this
				// code is only called when a connection to the database is already
				// established, thus the database name is guaranteed to be a correct
				// value.
				$query = "ALTER DATABASE \"" . $connection_options['database'] . "\" SET bytea_output = 'escape';";
				try {
					db_query($query);
				}
				catch (Exception $e) {
					// Ignore possible errors when the user doesn't have the necessary
					// privileges to ALTER the database.
				}

				// Close the database connection so that the configuration parameter
				// is applied to the current connection.
				db_close();

				// Recheck, if it fails, finally just rely on the end user to do the
				// right thing.
				if (!$this->checkBinaryOutputSuccess()) {
					$replacements = array(
							'%setting' => 'bytea_output',
							'%current_value' => 'hex',
							'%needed_value' => 'escape',
							'!query' => "<code>" . $query . "</code>",
					);
					$this->fail(st("The %setting setting is currently set to '%current_value', but needs to be '%needed_value'. Change this by running the following query: !query", $replacements));
				}
			}
		}
	}

	/**
	 * Verify that a binary data roundtrip returns the original string.
	 */
	protected function checkBinaryOutputSuccess() {
		$bytea_output = db_query("SELECT 'encoding'::bytea AS output")->fetchField();
		return ($bytea_output == 'encoding');
	}

	/**
	 * Make PostgreSQL Drupal friendly.
	 */
	function initializeDatabase() {
		// We create some functions using global names instead of prefixing them
		// like we do with table names. This is so that we don't double up if more
		// than one instance of Drupal is running on a single database. We therefore
		// avoid trying to create them again in that case.

		try {
			// Create functions.
			db_query('CREATE OR REPLACE FUNCTION "greatest"(numeric, numeric) RETURNS numeric AS
					\'SELECT CASE WHEN (($1 > $2) OR ($2 IS NULL)) THEN $1 ELSE $2 END;\'
					LANGUAGE \'sql\''
			);
			db_query('CREATE OR REPLACE FUNCTION "greatest"(numeric, numeric, numeric) RETURNS numeric AS
					\'SELECT greatest($1, greatest($2, $3));\'
					LANGUAGE \'sql\''
			);
			// Don't use {} around pg_proc table.
			if (!db_query("SELECT COUNT(*) FROM pg_proc WHERE proname = 'rand'")->fetchField()) {
				db_query('CREATE OR REPLACE FUNCTION "rand"() RETURNS float AS
						\'SELECT random();\'
						LANGUAGE \'sql\''
				);
			}

			db_query('CREATE OR REPLACE FUNCTION "substring_index"(text, text, integer) RETURNS text AS
					\'SELECT array_to_string((string_to_array($1, $2)) [1:$3], $2);\'
					LANGUAGE \'sql\''
			);

			// Using || to concatenate in Drupal is not recommeneded because there are
			// database drivers for Drupal that do not support the syntax, however
			// they do support CONCAT(item1, item2) which we can replicate in
			// PostgreSQL. PostgreSQL requires the function to be defined for each
			// different argument variation the function can handle.
			db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, anynonarray) RETURNS text AS
					\'SELECT CAST($1 AS text) || CAST($2 AS text);\'
					LANGUAGE \'sql\'
					');
			db_query('CREATE OR REPLACE FUNCTION "concat"(text, anynonarray) RETURNS text AS
					\'SELECT $1 || CAST($2 AS text);\'
					LANGUAGE \'sql\'
					');
			db_query('CREATE OR REPLACE FUNCTION "concat"(anynonarray, text) RETURNS text AS
					\'SELECT CAST($1 AS text) || $2;\'
					LANGUAGE \'sql\'
					');
			db_query('CREATE OR REPLACE FUNCTION "concat"(text, text) RETURNS text AS
					\'SELECT $1 || $2;\'
					LANGUAGE \'sql\'
					');

			$this->pass(st('PostgreSQL has initialized itself.'));
		}
		catch (Exception $e) {
			$this->fail(st('Drupal could not be correctly setup with the existing database. Revise any errors.'));
		}
	}
}

